To enable a single robot to perform a variety of processes, an output device is attached to a distal end of a robotic arm, and an adapter to which various types of tools are attached is fastened to the output device. Examples of known devices which are common with the output device in functions as a fastening device in a broad sense include a device described in Patent Literature 1 specified below, though it is not used in a state of being attached to a distal end of a robotic arm. The known art is structured as follows.
In the fastening device described in Patent Literature 1, an operating rod (driving spindle) is disposed orthogonally to an output rod (fastening-releasing driven wedge). The fastening device is configured so that: the operating rod is moved in its axial direction by rotating a hexagonal wrench inserted into a hexagonal hole provided to an end portion of the operating rod; and as a result, the output rod is moved via two wedges (a fastening driving wedge and a releasing driving wedge).